Dynamite has been known as blasting apparatus for blasting an object such as concrete or bedrock. However, dynamite is dangerous in view of its handling.
To eliminate such danger, there has recently been proposed a blasting apparatus and method allowing discharge energy to be used.
FIG. 32 shows the above-mentioned blasting apparatus 40, comprising a blasting probe 43 loaded in a loading hole 42 formed in a to-be-blasted object 41 and an electric energy supply circuit 45 for supplying electric energy to a fine metal wire 44 composing this blasting probe 43.
The above blasting probe 43 comprises a blasting vessel 46 inserted in the loading hole 42 in its depth direction and the above fine metal wire 44 connecting the tips of a pair of electrodes 47 and immersed into a blasting substance 48 filled in the blasting vessel 46.
A blasting method for blasting a to-be-blasted object 41 by using the blasting apparatus 40 comprises: forming a loading hole 42 on the surface of the to-be-blasted object 41; loading a blasting probe 43 in this loading hole 42; connecting an electric energy supply circuit 45 to the electrodes 47; and supplying to a fine metal wire 44 for a short time electric energy charged from a power supply device 49 and accumulated in a capacitor 51 via a charging control section 50 by way of discharging.
Then, the fine metal wire 44 rapidly melts and evaporates and evaporatively expands, causing a rapid expansion in volume of the blasting substance 48, whereby the to-be-blasted object 41 is blasted or becomes fragile by the resultant expansion force.
However, with the above blasting method using the above blasting apparatus 40, since the loading hole 42 for loading the blasting vessel 46 needs be formed in a to-be-blasted object 41, an excessive labor is required therefor. Such labor becomes especially heavy when many loading holes 42 must be formed in the to-be-blasted object 41 as shown in FIG. 33, which consequently requires a great amount of time for the work of blasting the object 41.
Such being the case, as shown in FIGS. 34 and 35, it is considered to employ a blasting vessel 46 placed along the surface of a to-be-blasted object 41 without forming loading holes 42. However, simply placing the blasting vessel 46 along the surface of the to-be-blasted object 41 caused dispersion of the expansion force (indicated by arrowheads in FIG. 35) generated when a fine metal wire 44 expands evaporatively and a blasting substance 48 expands in volume. In this result, the expansion force did not act on the object 41 effectively and could not surely blast the object 41.
It is a purpose of the present invention to provide a blasting apparatus and method capable of solving the above problems and a retainer member used for the same blasting method.